One-Shot Broadcast Joint Source-Channel Coding with Codebook Diversity
This work addresses the problem of reliable communication in one-shot broadcast scenarios, offering a new coding strategy that improves performance over existing approaches.
The paper studies one-shot joint source-channel coding with a broadcast setup, where a source is encoded once and sent to K decoders. It introduces a codebook diversity gain from using disjoint codebooks at decoders, distinct from channel diversity. A hybrid coding scheme balancing codebook and channel diversity is proposed, outperforming fully shared or disjoint codebooks on binary symmetric channels.
We study a one-shot joint source-channel coding setting where the source is encoded once and broadcast to $K$ decoders through independent channels. Success is predicated on at least one decoder recovering the source within a maximum distortion constraint. We find that in the one-shot regime, utilizing disjoint codebooks at each decoder yields a codebook diversity gain, distinct from the channel diversity gain that may be expected when several decoders observe independent realizations of the channel's output but share the same codebook. Coding schemes are introduced that leverage this phenomenon, where first- and second-order achievability bounds are derived via an adaptation of the Poisson matching lemma which allows for multiple decoders using disjoint codebooks. We further propose a hybrid coding scheme that partitions decoders into groups to optimally balance codebook and channel diversity. Numerical results on the binary symmetric channel demonstrate that the hybrid approach outperforms strategies where the decoders' codebooks are either fully shared or disjoint.